Assessment of Intra-Varietal Diversity among Biotypes of the cv. Cannonau (

Grapevine cultivars may exhibit significant intra-varietal variability resulting from somatic mutations accumulated during long-term vegetative propagation and from historical massal selection practices. Cannonau (syn. Garnacha) is one of the most important grapevine cultivars cultivated in Sardinia, where it has been grown for centuries under heterogeneous Mediterranean environments. This study aimed to assess the phenotypic variability among Cannonau biotypes under uniform environmental conditions. Eighty-three biotypes identified through a massal selection program were evaluated in a single experimental vineyard during the 2022 and 2023 growing seasons. Agronomic traits, vegetative vigor and berry composition were recorded, and multivariate statistical analyses (MFA and HCPC) were applied to explore variability patterns. The results revealed a wide range of variation in yield, vegetative vigor, berry sugar concentration and total anthocyanins. Multivariate analysis identified three groups of biotypes characterized by distinct agronomic and compositional profiles. These findings confirm the presence of significant intra-varietal diversity within Cannonau germplasm and highlight its potential for the selection of plant material suited to different viticultural and oenological objectives.